You do realize stereotyping and having prejudice are two different things, right? Just because an elf, let's say, thinks he's better than a dwarf doesn't mean he thinks he's better than an elf of the female persuasion, but may think that the stereotype of the brainy brunette as appealing. 
It's not even as if Dext says there is [i]no[/i] sexism; he says it just is has never been an issue. Making the assumption that it has never existed, even in a single individual, simply because he says these fictional people have never had an issue with it is a fallacy on its own.

EDIT: Skys and I are also working on our character, btw. :P